1. Field
Apparatuses and methods consistent with exemplary embodiments broadly relate to a light emitting diode driver circuit, a display apparatus including the same, and a method for driving a light emitting diode, and more particularly, to a light emitting diode driver circuit, a display apparatus including the same, and a method for driving a light emitting diode that may prevent flicker by varying a frequency of a clock signal according to a state value of a dimming signal.
2. Description of the Related Art
A liquid crystal display (LCD) that has a thin thickness, light weight, and low driving voltage and consumption power when compared to other displays is widely used. However, since the liquid crystal display is a non-emissive element that does not autonomously emit light, it has a need for a separate backlight for supplying light to a liquid crystal display panel.
As a backlight light source of the liquid crystal display, a cold cathode fluorescent lamp (CCFL), a light emitting diode (LED), and the like are often used. The cold cathode fluorescent lamp (CCFL) had disadvantages that since it uses mercury, it may cause environmental pollution, has a slow response speed, has a low color reproducibility, and is not suitable for thinness and lightness of the LCD panel.
On the other hand, the light emitting diode has advantages that since it does not use an environmental harmful substance, it is environmentally friendly, and an impulse driving is possible. Further, the light emitting diode has advantages in that it has excellent color reproducibility, it may arbitrarily change luminance, color temperature, and the like, by controlling an amount of light of red, green, and blue light emitting diodes. It is also suitable for thinness and lightness of the LCD panel. Accordingly, recently, the light emitting diode is often employed as the backlight light source of the LCD panel, and the like.
As such, in an LCD backlight employing the light emitting diode, a current supplied to the light emitting diode is varied in response to brightness information of an image for improving image quality and reducing power consumption.
Such current supplied to the light emitting diode is performed in a unit of clock period in an integrated circuit (IC) that controls an LED driver circuit. If an operating timing between the clock period and a dimming signal corresponding to the brightness information is different, there is a case in which different constant currents are provided to the light emitting diode every period of the dimming signal. Particularly, there was a problem of flickering due to very large brightness difference when a dimming duty of the dimming signal is low; that is, a gray scale of a low brightness is represented.